Conduit plug

ABSTRACT

A plug assembly for sealing the open end of a conduit, which assembly includes a resilient plug on the opposite sides of which are disposed a pair of plates which are drawn toward one another to apply pressure to the plug sandwiched therebetween. Under pressure, the plug expands into sealing relationship with the interior of the conduit. The plug includes angularly oriented side surface areas which are engaged by similarly oriented portions of the side plates such that pressure developed between the plates is laterally distributed across the thickness of the plug whereby an area contact of engagement can be established between the perimeter of the plug and the interior of the conduit. Alternatively, or in addition thereto, a central side surface of the plug is concavely bowed with respect to a central plane thereof such that a flat central mating portion of the cooperating plate member, when applied thereto, will establish an area contact of engagement between the central portion of the thickness of the perimeter of the plug and the interior of the conduit.

June 6, 1972 United States atent Morrow ABSTRACT CONDUIT PLUG Inventor: Joseph G. Morrow, P. O. Box 21 1, Ea A plug assembly for sealing the open end of a conduit, which Pat r on, N J 07013 assembly includes a resilient plug on the opposite sides of which are disposed a pair of plates which are drawn toward July 13, 1970 [22] Filed: one another to apply pressure to the plug sandwiched [2i] therebetweenv Under pressure, the plug expands into sealing Appl. No.:

relationship with the interior of the conduit. The plug includes Related Appllcatlon Data angularly oriented side surface areas which are engaged by Continuation of Ser. No. 778,499, Nov. 25, 1968, abandoned.

similarly oriented portions of the side plates such that pressure developed between the plates is laterally distributed across the thickness of the plug whereby an area contact of engagement [52] us. can be established between the perimeter of the plug and the Int. .B65d 39/12 interior of the conduit. Alternatively, or in addition thereto, a

,54; central side surface of the plug is concavely bowed with [58] Field of Search 178/89 respect to a central plane thereof such that a flat central mating portion of the cooperating plate member, when applied thereto, will establish an area contact of engagement between the central portion of the thickness of the perimeter of the plug and the interior ofthe conduit.

References Cited UNITED STATES PATENTS 6 Claims, 11 Drawing Figures 680,750 8/1901 Winterlich 2,479,862 8/1949 6 n y a P Primary Examiner-Raphael H. Schwartz Attorney-Lawrence I. Lerner PATENT Elma 6 I972 SHEET 10F 2 IN VENTOR. JOSEPH G. MORROW PATENTED UH 6 1912 3. 667. 640

SHEET 2 0F 2 INVE R. JOSEPH G. 0W

CONDUIT PLUG This is a continuation of my copending application Ser. No. 778,499, filed Nov. 25, 1968, and entitled CONDUIT PLUG, now abandoned.

BACKGROUND OF THE INVENTION This invention relates to plug assemblies for sealing the open end of a conduit, and more particularly relates to such plug assemblies which are capable of establishing an area contact between the exterior peripheral surface of such plugs and the interior of the conduit being sealed.

There are many situations where it is desirable to seal the open end of a conduit. For example, when laying telephone or power conduit underground, it is critically important that open ends of such conduit, usually in manholes, be effectively sealed from moisture and other contaminates. If these conduits are not tightly sealed silt, water rodents, seepage, etc., can restrict conduit openings thereby making subsequent cable installation very difficult.

Prior art plug assemblies for sealing the open end of such conduits generally comprose a resilient plug which in its relaxed position, is slightly smaller than the interior configura tion of the conduit being sealed. Positioned on opposite sides of the plug are a pair of plates which can be drawn toward one another to squeeze the plug to a compressed condition in which the outer periphery of the plug engages the interior surface of the conduit. However, available plug assemblies of this type, suffer from a serious disadvantage which the instant invention effectively overcomes Thus the compressible plugs of prior art plug assemblies, are cylindrical in nature; and when they are compressed by the application of pressure from opposite sides thereof, the peripheral surface thereof bulges in such a manner as to establish only a tangential line of contact between the plug and the interior surface of the conduit. As may be appreciated, such tangential lines of engagement between the plug and the interior surface of the conduit, are relatively ineffective in sealing the interior of the conduit from the moisture and contaminates of the soil nearby. Additionally, the problem is acute over extended periods of time during which the conduits lay dormant in the ground since low water-table water pressure can physically force out the plug.

SUMMARY OF THE INVENTION In contradistinction thereto, the instant invention provides a plug assembly for sealing the open end ofa conduit, but which plug assembly is capable of establishing an area contact between the peripheral of the resilient plug thereof and the interior surface of the conduit. The relatively large area contact established by the plug assembly of the instant invention substantially increases the effectiveness of the seal established thereby such that underground telephone conduits, and indeed all conduits, can be protected from their outside environ ment for virtually an indefinite length of time. In various embodiments of the instant invention, the above noted area engagement between a plug assembly and the interior ofa conduit is established by so configuring the opposite sides of the resilient plug of such assembly that similarly shaped portions of the cooperating plate members will distribute components of the pressure developed thereby radially along portions of the thickness of the compressed plug.

In one embodiment, an annular inclined side surface is provided on at least one side of the resilient plug and a similarly oriented plate portion is provided on the plate member which cooperates therewith. When the plates are drawn toward one another to compress the plug, the lateral distribution of radially directed pressure components produced thereby will establish an area contact between the extremity of the plug and the interior surface of the conduit. In an alternative embodiment, or in addition thereto, a central portion of the resilient plug is provided with an exterior surface concavely bowed with respect to a longitudinal plane passing through the center of the plug. When the flat central portion of the plate that cooperates therewith is drawn toward the center of the plug, a flat area contact is established between the central portion of the thickness of the plug and the interior surface of the conduit, rather than the bowed effect of the prior art.

Accordingly, it is an object of the instant invention to provide a plug assembly for sealing the open end of a conduit.

Another object of the instant invention is to provide such a plug assembly which is capable of establishing an area contact between the perimeter of the plug thereof and the interior surface of the conduit.

Still another object of the instant invention is to provide such a plug assembly which includes a pair of plate members between which is located a resilient plug capable of being compressed from a relaxed state to a compressed state which sealing engages the interior surface of a conduit.

Another object of the instant invention is to provide such a plug assembly which includes manually operable draw means for drawing such plate members toward one another to compress the plug therebetween.

Yet another object of the instant invention is to provide such a plug assembly wherein the plug thereof is provided with configured side surface areas which cooperate with mating portions of the above noted plate members to laterally distribute radially directed pressure components across the thickness of the compressible plug.

Yet another object of the instant invention is to provide such a plug assembly wherein such side surface areas are angularly inclined and are engaged by similarly angularly inclined portions of the cooperating plate members.

Yet another object of the instant invention is to provide such a plug assembly wherein the side surface areas include a concavely bowed surface which when compressed by a flat portion of the cooperating plate member establishes an area contact across the central portion of the thickness of the resilient plug.

These and other objects of the instant invention and further understanding thereof may be had by referring to the following specification and drawings in which:

FIG. 1 is an exploded perspective view of a plug assembly constructed in accordance with the teaching of the instant invention;

FIG. 2 is a cross-sectional view of the plug assembly of FIG. 1 in its relaxed condition;

FIG. 3 is a cross-sectional view of the plug assembly of FIGS. 1 and 2 in its compressed condition;

FIG. 3A is a partial view, in section, of an alternative embodiment of the instant invention;

FIG. 3B is a partial view, in section, of yet another embodiment of the instant invention;

FIG. 4 is a plan view of an alternative embodiment of a plate member utilized in the plug assembly of FIG. 1;

FIG. 4A is a view taken along the arrows 4A-4A of FIG. 4;

FIG. 5 is a plan view of yet another alternative embodiment of the plate of FIG. 4;

FIG. 5A is a view taken along the arrows SA-SA of FIG. 5;

FIG. 6 is a plan view of yet another alternative embodiment of the plate member utilized in the plug assembly of FIG. 1; and

FIG. 6A is a view taken along the arrows 6A-6A of FIG. 6.

Turning to FIG. 1, there is shown in an exploded perspective view, the plug assembly 10 of the instant invention which is intended to seal the open end of a hollow cylindrical conduit 12. Although the conduit 12 of FIG. 1 happens to be illustrated as cylindrical in configuration, it will be shown that the instant invention is equally as applicable to sealing the interior of other shaped conduits for example of rectangular cross-section. The plug assembly includes plug 14 of rubber or other resilient material, the only requirement being that the plug be capable of being compressed, in a manner to be further described, from a relaxed state illustrated in FIG. 2 to a compressed state as illustrated in FIG. 3.

Positioned on opposite sides of the plug 14 are a pair of plate members 16 and 18 which when drawn toward one another, apply the pressure which converts the plug 14 from its relaxed state of FIG. 2 to the compressed state of FIG. 3. The plug 14 and plates 16 and 18 include centrally located apertures 20, 22, and 24 respectively, through which passes a bolt 26. As best seen in FIG. 1, the head end of the bolt 26 includes a keyed section 30 which when residing within the similarly shaped aperture 24, will prevent the bolt 26 from rotating when the nut 32 is tightened on the threads of the bolt 26. If desired, a metal sleeve 27 may be molded into the plug 14 to act as a stop which will prevent overtightening. When the plug is in the relaxed state the sleeve 27 would have a length less than the thickness of the plug by a preselected amount corresponding to the amount of tightening which one wishes the plug to withstand.

As illustrated in FIG. 1, the plug assembly including the plug 14 and plate members 16 and 18 is of a similar peripheral configuration as the interior of the conduit 12 which it is intended to seal. However, the diameters of components of the plug assembly are somewhat smaller than the internal diameter of the conduit 12 such that when the plug assembly is in the relaxed state of FIG. 2, it can be easily slid into the open end of the conduit. It is only when the nut 32 is tightened such that the plates 16 and 18 are drawn toward one another, that the plug 14 diametrically expands and is sealingly urged into engagement with the interior surface of the conduit 12.

As noted previously, prior art plug assemblies of the type including a pair of plate members between which is sandwiched a resilient plug have suffered from the serious drawback that only a tangential line of contact is established between the compressed plug and the interior of the conduit being sealed. This problem stems from the fact that the plugs of the prior art assemblies have been substantially cylindrical such that when compressed, the external peripheral surface thereof bows outwardly whereby only the crest of the bowed plug comes into tangential contact with the interior of the conduit. The manner in which the instant invention overcomes this problem by establishing a relatively large area contact between the peripheral surface of the plug and the interior of the conduit can best be understood by referring to FIGS. 2 and 3.

Turning to FIG. 2, it will be seen that one side 34 of the plug 14 is provided with an annular side surface area 36 which is angularly inclined away from a longitudinal plane illustrated by the phamtom line 8 passing centrally through the plug 14. The opposite side 40 of the plug 14 similarly includes an annular side surface area which is of similar angle but in the op posite direction with respect to the central plane 38. The plate members 18 and 16 likewise include annular side surface portions 44 and 46 which are urged into contact with their respective side surface areas 36 and 42 of the plug 14 when the plate members 18 and 16 are drawn toward one another by tightening the nut 32.

Disregarding for a moment the effects of the concavely bowed exterior surfaces 48 and 50 of the plug 14, the effect of the cooperating angled surfaces of the plug and plate members respectively can be explained as follows: As the nut 32 is tightened on the bolt 26, inwardly directed pressure components illustrated by the arrows 52 are established. However, because of the angled side surface areas 36, 42 and mating plate portions 44, 46 respectively, radially directed components illustrated by the arrows 54 of FIG. 2 will be distributed laterally across portions 56 of the thickness of the plug 14. The result is best seen in FIG. 3 wherein the plug 14 has been compressed so as to swell diametrically such that an area contact will be established between portions 56 and the interior surface of the conduit 12, the area of contact in this case being twice the width of a thickness portion 56 times d where d is the inside the diameter of the conduit 12.

Returning now to FIG. 2, it was previously disclosed that a central portion of the plug 14 includes concavely bowed exterior surfaces 48 and 50. These surfaces when compressed by the central flat portions 58 and 60 of their respective plate members 16 and 18 distribute radial components of force laterally across the central thickness 62 of the exterior of the plug 14 which lies between the previously identified portions 56. Thus as seen in FIG. 3, when the plug is compressed, the otherwise concavely bowed middle portion of the plug will be filled in as illustrated at 62 in FIG. 3 such that in the end result, the entire thickness of the plug 14 will be urged into sealing area contact with the interior of the conduit 12.

It is to be understood, that in a preferred embodiment of the instant invention, both the inclined side surface areas 36, 42 and the concavely bowed central areas of the plug 48, 50 are utilized to establish an area contact along the entire thickness of the plug 14. Thus one viewing a cross-section of the compressed plug would not actually see a separate center section 62 as illustrated in FIG. 3. The seperately delineated section 62 of FIG. 3 is presented only to illustrate the cumulative effect of the bowed exterior surfaces 48 and 50 of the plug 14. If desired, such concavely bowed surfaces 48 and 50 could be eliminated such that the exterior perimeter of the plug of FIG. 3 would have a somewhat concavely bowed cross-section (without the center section 62 being present) but the area contact would still be established along the portions 56. On the other hand, if desired, the angularly inclined cooperating side surfaces 36, 42 could be eliminated and instead only the concavely bowed surfaces 48 and 50 utilized so as to establish an area of contact 62 of FIG. 3A intermediate the ends of the plug 14. Either embodiment or a combination of both, will establish the desirable area contact.

FIG. 38 illustrates yet other features of the invention which can, if desired, be added to a plug 14 having only the side surface areas 36, 42; only the concavely bowed surfaces 48, 50; or both. Thus, the relaxed plug of FIG. 3B can have rounded edges 63 to facilitate its insertion into the open conduit 12. Also, the plug can be provided with a pair of small annular projections 65 thereabout, near the outer edges thereof which aid in sealing when the plug is compressed.

Turning to FIGS. 4 and 4A there is shown a plate member 8 which, with the exception of its external peripheral configuration, is similar to the plate 18 of FIGS. 13. Thus the plate 18 includes the angularly oriented portions 44' and a central planar portion 58 which would immediately cooperate with inclined side surface areas and concavely bowed central areas of a resilient plug associated therewith. As noted, the primary difference in the plug 18' of FIG. 4 is its somewhat square outline which is intended to suggest that such plate members and a correspondingly shaped square plug 14 could cooperate to define a plug assembly which would be used to seal the interior of a generally rectangular or square conduit. Also FIG. 4 illustrates the use of plates with ribbing 67 to add strength.

Turning to FIGS. 5 and 5A, there is illustrated another type of plate member 18" which is basically similar to the plate 18 of FIGS. 4 and 4A. The only difference between the plate members of FIGS. 4 and 5 is that the plate member of FIG. 4 includes a rim 64 thereabout (similar to the rims 66 of plate members 16 and 18 of FIG. 2).

Similarly, FIGS. 6 and 6A illustrate plate members 18" generally similar to the plate members 16 and 18 of FIGS. 1-3 but without the restraining rims 66 thereabout. It is to be understood that all of the various plate members illustrated will function without the rims 66 but that the use of such rim is preferred since the rims aid in constraining the plug to expansion along its diameter.

Thus there has been described a plug assembly for sealing the open end of a conduit which assembly includes a resilient plug sandwiched between a pair of plate members which when drawn toward one another will cause the longitudinal expansion of the plug into sealing contact with the interior of the conduit. By the use of novel pressure distribution means, the compressed plug is sealingly urged into an area contact with the interior of the conduit, thereby representing a substantial advancement over the tangential line of contact established by the prior art.

Although this invention has been described with respect to its preferred embodiments, it should be understood that many variations and modifications will now be obvious to those skilled in the art, and it is preferred, therefore, that the scope of the invention be limited, not by the specific disclosure herein, only by the appended claims.

I claim:

1. A plug assembly for sealing a conduit; said plug comprising:

compressible plug means capable of being transformed from a relaxed condition to a compressed condition by the application of pressure from opposite sides thereof, said plug means having a peripheral configuration corresponding to the interior configuration of the conduit said plug assembly is intended to seal, said peripheral configuration being smaller than said interior configuration when said plug means is in its relaxed condition, said peripheral configuration swelling to engage said interior configuration when said plug means is in its compressed condition;

pressure application means for transforming said plug means from its relaxed condition to its compressed condition; said pressure application means including;

pressure distribution means cooperating with said plug means for establishing area contact between the interior of said conduit and said plug means around the entire perimeter ofsaid plug means,

said pressure application means including first and second plate members positioned on opposite sides of said plug means and further including operable draw means for drawing said first and second plate members toward one another,

said plug means including at least one side surface area on a first side thereof angularly oriented with respect to a cross-sectional plane longitudinally disposed through the center of said plug means,

said pressure distributing means comprising at least one similarly angularly oriented portion of said first plate means which is urged into engagement with said one side surface when said draw means is operated to draw first and second plate members towards one another,

said plug means further including a second side surface area on the opposite side of said plug means which is angularly oriented with respect to said plane,

said pressure distributing means further including a portion of said second plate member which is urged into engagement with said second side surface area when said draw means is operated to draw said first and second plates towards one another,

said first and second side surfaces being similarly angled with respect to said plane but in opposite directions with respect thereto,

said first and second side surface areas being angularly disposed toward the outer extremity of said plug means and defining annular rings around said plug means,

said plug means further including a central portion having the exterior surfaces thereof convexly bowed with respect to said plane,

said pressure distribution means further comprising flat portions on each of said first and second plate members which are urged into engagement with said convexly bowed exterior surfaces when said draw means is operated to draw said first and second plate member toward one another,

whereby the components of the pressure developed by said pressure application means will be laterally distributed across the thickness of said plug means to establish area contact between the interior of said conduit and said plug means around the entire perimeter of said plug means.

2. The plug assembly of claim 1 wherein said angularly oriented side surface area extends around said plug means on said first side thereof to define an annular ring within which is located said convexly bowed central portion.

3. The plug assembly of claim 1 wherein said fiat portion of said first plate includes rib means for adding strength thereto.

4. The plug assembly of claim 1 wherein said plug means includes cylindrical sleeve means located therein for preventing said operable draw means from overdrawing said first and second plates toward one another.

5. The plug assembly of claim 1 wherein said plug means is provided with projection means adjacent the edge of its outer periphery to aid in establishing an effective seal between said plug means and said conduit when said plug means is compressed.

6. A plug assembly for sealing a conduit; said plug comprising:

compressible plug means capable of being transformed from a relaxed condition to a compressed condition by the application of pressure from opposite sides thereof, said plug means having a peripheral configuration corresponding to the interior configuration of the conduit said plug assembly is intended to seal said peripheral configuration being smaller than said interior configuration when said plug means is in its relaxed condition, said peripheral configuration swelling to engage said interior configuration when said plug means is in its compressed condition;

pressure application means for transforming said plug means from its relaxed condition to its compressed condition; said pressure application means including:

pressure distribution means cooperating with said plug means for establishing area contact between the interior of said conduit and said plug means around the entire perimeter of said plug means,

said pressure application means including first and second plate members positioned on opposite sides of said plug means and further including operable draw means for drawing said first and second plate members toward one another,

said plug means including at least one side surface area on a first side thereof angularly oriented with respect to a cross-sectional plane longitudinally disposed through the center of said plug means,

said pressure distributing means comprising at least one similarly angularly oriented portion of said first plate means which is urged into engagement with said one side surface when said draw means is operated to draw first and second plate members towards one another,

said plug means further including a second side surface area on the opposite side of said plug means which is angularly oriented with respect to said plane,

said pressure distributing means further including a portion of said second plate member which is urged into engagement with said second side surface area when said draw means is operated to draw said first and second plates towards one another,

said first and second side surfaces being similarly angled with respect to said plane but in opposite directions with respect thereto,

said first and second side surface areas being angularly disposed toward the outer extremity of said plug means and defining annular rings around said plug means,

said plug means further including a central portion having first and second exterior surfaces, at least one of said exterior surfaces including a portion raised further from said plane than remaining portions of said one exterior surface,

said pressure distribution means further comprising flat portions on each of said first and second plate members which are urged into engagement with said first and second exterior surfaces when said draw means is operated to draw said first and second plate member toward one another,

whereby the components of the pressure developed by said pressure application means will be laterally distributed across the thickness of said plug means to establish area contact between the interior of said conduit and said plug means around the entire perimeter of said plug means. 

1. A plug assembly for sealing a conduit; said plug comprising: compressible plug means capable of being transformed from a relaxed condition to a compressed condition by the application of pressure from opposite sides thereof, said plug means having a peripheral configuration corresponding to the interior configuration of the conduit said plug assembly is intended to seal, said peripheral configuration being smaller than said interior configuration when said plug means is in its relaxed condition, said peripheral configuration swelling to engage said interior configuration when said plug means is in its compressed condition; pressure application means for transforming said plug means from its relaxed condition to its compressed condition; said pressure application means including; pressure distribution means cooperating with said plug means for establishing area contact between the interior of said conduit and said plug means around the entire perimeter of said plug means, said pressure application means including first and second plate members positioned on opposite sides of said plug means and further including operable draw means for drawing said first and second plate members toward one another, said plug means including at least one side surface area on a first side thereof angularly oriented with respect to a crosssectional plane longitudinally disposed through the center of said plug means, said pressure distributing means comprising at least one similarly angularly oriented portion of said first plate means which is urged into engagement with said one side surface when said draw means is operated to draw first and second plate members towards one another, said plug means further including a second side surface area on the opposite side of said plug means which is angularly oriented with respect to said plane, said pressure distributing means further including a portion of said second plate member which is urged into engagement with said second side surface area when said draw means is operated to draw said first and second plates towards one another, said first and second side surfaces being similarly angled with respect to said plane but in opposite directions with respect thereto, said first and second side surface areas being angularly disposed toward the outer extremity of said plug means and defining annular rings around said plug means, said plug means further including a central portion having the exterior surfaces thereof convexly bowed with respect to said plane, said pressure distribution means further comprising flat portions on each of said first and second plate members which are urged into engagement with said convexly bowed exterior surfaces when said draw means is operated to draw said first and second plate member toward one another, whereby the components of the pressure developed by said pressure application means will be laterally distributed across the thickness of said plug means to establish area contact between the interior of said conduit and said plug means around the entire perimeter of said plug means.
 2. The plug assembly of claim 1 wherein said angularly oriented side surface area extends around said plug means on said first side thereof to define an annular ring within which is located said convexly bowed central portion.
 3. The plug assembly of claim 1 wherein said flat portion of said first plate includes rib means for adding strength thereto.
 4. The plug assembly of claim 1 wherein said plug means includes cylindrical sleeve means located therein for preventing said operable draw means from overdrawing said first and second plates toward one another.
 5. The plug assembly of claim 1 wherein said plug means is provided with projection means adjacent the edge of its outer periphery to aid in establishing an effective seal between said plug means and said conduit when said plug means is compressed.
 6. A plug assembly for sealing a conduit; said plug comprising: compressible plug means capable of being transformed from a relaxed condition to a compressed condition by the application of pressure from opposite sides thereof, said plug means having a peripheral configuration corresponding to the interior configuration of the conduit said plug assembly is intended to seal said peripheral configuration being smaller than said interior configuration when said plug means is in its relaxed condition, said peripheral configuration swelling to engage said interior configuration when said plug means is in its compressed condition; pressure application means for transforming said plug means from its relaxed condition to its compressed condition; said pressure application means including: pressure distribution means cooperating with said plug means for establishing area contact between the interior of said conduit and said plug means around the entire perimeter of said plug means, said pressure application means including first and second plate members positioned on opposite sides of said plug means and further including operable draw means for drawing said first and second plate members toward one another, said plug means including at least one side surface area on a first side thereof angularly oriented with respect to a cross-sectional plane longitudinally disposed through the center of said plug means, said pressure distributing means comprising at least one similarly angularly oriented Portion of said first plate means which is urged into engagement with said one side surface when said draw means is operated to draw first and second plate members towards one another, said plug means further including a second side surface area on the opposite side of said plug means which is angularly oriented with respect to said plane, said pressure distributing means further including a portion of said second plate member which is urged into engagement with said second side surface area when said draw means is operated to draw said first and second plates towards one another, said first and second side surfaces being similarly angled with respect to said plane but in opposite directions with respect thereto, said first and second side surface areas being angularly disposed toward the outer extremity of said plug means and defining annular rings around said plug means, said plug means further including a central portion having first and second exterior surfaces, at least one of said exterior surfaces including a portion raised further from said plane than remaining portions of said one exterior surface., said pressure distribution means further comprising flat portions on each of said first and second plate members which are urged into engagement with said first and second exterior surfaces when said draw means is operated to draw said first and second plate member toward one another, whereby the components of the pressure developed by said pressure application means will be laterally distributed across the thickness of said plug means to establish area contact between the interior of said conduit and said plug means around the entire perimeter of said plug means. 